The present invention relates generally to a spindle assembly for a rotary grass trimmer.
More particularly, this invention pertains to an adjustable spindle assembly for a push-type rotary grass trimmer that includes a mow ball rotatably connected to a spindle shaft and allows the attachment of cutting strings or filaments without the use of tools.
Although spindle assemblies for rotary grass trimmers are known in the art, the current versions have several problems. For example, U.S. Pat. No. 5,313,770, issued to Smothers on May 24, 1994 and entitled xe2x80x9cJam-Proof Rotary Weed Cutter,xe2x80x9d discloses a push-type grass trimmer having a spool rigidly connected to a drive shaft. The shaft and spool are driven at a high rate of speed by a motor and, when the trimmer is used, the spool comes into contact with the ground a significant amount of time. As a result, the spool rubs against the ground, wears down, and must be replaced. This result is undesirable because replacing the spool costs time and money. As a result, there is a need for a spindle assembly that reduces the amount of wear on the spool when the spool is in use.
Current spindle assembles also require the use of tools to secure the cutting string or filament to the spool and to adjust the cutting height of the string. U.S. Pat. No. 5,862,655, issued to Altamirano et al. on Jan. 26, 1999 and entitled xe2x80x9cAdjustable Mowing and Trimming Apparatus,xe2x80x9d discloses a push-type grass trimmer that includes an adjustable trimmer head that is connected to a spindle head using a threaded fastener, i.e., a bolt and nut. In addition, the cutting string is also connected to the trimmer head using a bolt and nut. U.S. Pat. No. 6,052,974, issued to Harb on Apr. 25, 2000 and entitled xe2x80x9cAdjustable Height Head For String Trimmer,xe2x80x9d also discloses a string trimmer that uses bolts to secure the cutting string to the trimmer head and to secure the adjustable trimmer head in place.
Since bolts are used to secure the trimmer head and cutting string, a separate tool, such as a wrench, must be used to loosen or tighten the bolts in order to adjust the cutting height or to replace the cutting string. The requirement for a separate tool is undesirable because, in some cases, the required tool may not be readily available. Furthermore, the use of a bolt and nut to secure the trimmer head and cutting string increases the amount of time it takes to replace the cutting string or adjust the height of the trimmer head. Thus, there is a need for a spindle assembly that includes a means for adjusting the cutting height of the trimmer head and attaching the string to the trimmer head that does not require the use of a separate tool.
What is needed, then, is a spindle assembly that reduces the amount of wear on the spool and eliminates the need for a separate tool to adjust the cutting height and to replace the cutting string.
The present invention satisfies the above described need by providing a spindle assembly that includes a spool, or alternatively, a mow ball, that is rotatably connected to a spindle shaft, a string assembly that is adjustably connected to the spindle shaft between a spindle housing and the mow ball, and wherein the string assembly includes a pair of string guides and string holders for securing cutting string to the string assembly without a separate tool.
In one embodiment, the present invention includes a spindle housing, a spindle shaft rotatably connected to the spindle housing, a pulley connected to one end of the spindle shaft, a mow ball rotatably connected to the opposite end of the spindle shaft, and a string carrier plate having a pair of string guides and s-shaped string holders connected between the spindle housing and the mow ball.
In a second embodiment, the spindle assembly of the present invention includes a spindle housing, a grooved spindle shaft rotatably connected to the spindle housing, a pulley connected to one end of the grooved spindle shaft, a mow ball rotatably connected to the opposite end of the grooved spindle shaft, and a string carrier assembly adjustably connected to the grooved spindle shaft between the spindle housing and the mow ball. The grooved spindle shaft includes a series of locking grooves and the string carrier assembly includes a locking slide and a spring, which can be used in conjunction with the locking grooves to secure the string carrier assembly at various positions between the spindle housing and the mow ball without using a separate tool. The string carrier assembly includes a string carrier plate that includes a pair of string guides and s-shaped string holders that may be used to secure cutting string to the string carrier plate without using a separate tool.
In a third embodiment, the spindle assembly of the present invention includes a spindle housing, a keyed spindle shaft rotatably connected to the spindle housing, a pulley connected to one end of the keyed spindle shaft, a mow ball rotatably connected to the opposite end of the keyed spindle shaft, an exteriorly threaded height adjustment tube connected to the mow ball, and a string cutting assembly adjustably connected to the height adjustment tube between the spindle housing and the mow ball using a locking plate. The string cutting assembly includes a threaded opening for receiving the threaded portion of the height adjustment tube and can be adjusted by releasing the locking plate, rotating the string cutting assembly with respect to the height adjustment tube clockwise or counterclockwise, and engaging the locking plate. The string cutting assembly includes a pair of v-shaped string holders for securing cutting string to the string cutting assembly without using a separate tool.